SAN FRANCISCO (Reuters) - A group including a California nonprofit organization is suing fish oil manufacturers and pharmacies that sell the popular supplements over their purported toxicity.

The lawsuit, filed Tuesday in San Francisco Supreme Court, claims that the makers and sellers of certain supplements found to contain high levels of PCB compounds - man-made industrial chemicals - have failed to alert consumers as required under California's right-to-know law.

The Mateel Environmental Justice Foundation, one of three named plaintiffs, tested 10 fish oil supplements out of more than 100 on the market. The other plaintiffs in the case are New Jersey residents.

Defendants include the world's largest producer of omega-3 fish oil, Houston-based Omega Protein, as well as drug stores Rite Aid Corp and CVS Caremark Corp .

"The people buying these fish oil supplements are not being told the PCBs are there," said plaintiff's attorney David Roe.

People consume fish oil supplements for the health benefits obtained from omega-3 fatty acids, but there are currently no standards for PCB contamination in the United States, according to Roe.

Also named as defendants are General Nutrition Corp, a subsidiary of GNC Acquisition Holdings Corp, Now Health Group Inc, Pharmavite LLC, the maker of the NatureMade brand of supplements, Solgar Inc and TwinLab Corp.